scholarly journals A Comparative Study of Analytical Rosenthal, Finite Element, and Experimental Approaches in Laser Welding of AA5456 Alloy

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 436 ◽  
Author(s):  
Hamidreza Hekmatjou ◽  
Zhi Zeng ◽  
Jiajia Shen ◽  
J. P. Oliveira ◽  
Homam Naffakh-Moosavy
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Laser Welding ◽  
High Energy ◽  
Experimental Results ◽  
High Energy Density ◽  
Analytical Equation ◽  
Fe Model ◽  
Melt Pool ◽  
Analytical Approaches

The thermal regime and microstructural phenomenon are studied by using finite-element (FE) modelling and the analytical Rosenthal equation during laser welding of aluminum alloy 5456 (AA5456) components. A major goal is to determine the merits and demerits of this analytical equation which can be an alternative to FE analysis, and to evaluate the effect of imperative assumptions on predicted consequences. Using results from the analytical and numerical approaches in conjunction with experiments, different physical features are compared. In this study, the results obtained from experiments in terms of melt pool shapes are compared with the predicted ones achieved from the numerical and analytical approaches in which the FE model is more accurate than the Rosenthal equation in the estimation of the melt pool dimensions. Furthermore, as to the partially melted zones, the estimations achieved from the numerical modeling are more genuine than ones from the analytical equation with regards to the experimental results. At high energy density, near keyhole welding mode, the reported results show that experimental melt widths are supposed to be narrower than the fusion widths estimated by the analytical solution. The primary explanation could be the influence of thermal losses that occurred during convection and radiation, which are neglected in the Rosenthal equation. Additionally, the primary dendrite arm spacing (PDAS) estimated with the numerical modeling and the analytical Rosenthal solution is comparable with the experimental results obtained.

scholarly journals A Compact Review of Laser Welding Technologies for Amorphous Alloys

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1690
Author(s):  
Jian Qiao ◽  
Peng Yu ◽  
Yanxiong Wu ◽  
Taixi Chen ◽  
Yixin Du ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Laser Welding ◽  
Amorphous Alloys ◽  
High Energy ◽  
Industrial Applications ◽  
High Energy Density ◽  
Current Status ◽  
Future Research ◽  
Technological Parameters ◽  
Fast Heating

Amorphous alloys have emerged as important materials for precision machinery, energy conversion, information processing, and aerospace components. This is due to their unique structure and excellent properties, including superior strength, high elasticity, and excellent corrosion resistance, which have attracted the attention of many researchers. However, the size of the amorphous alloy components remains limited, which affects industrial applications. Significant developments in connection with this technology are urgently needed. Laser welding represents an efficient welding method that uses a laser beam with high energy-density for heating. Laser welding has gradually become a research hotspot as a joining method for amorphous alloys due to its fast heating and cooling rates. In this compact review, the current status of research into amorphous-alloy laser welding technology is discussed, the influence of technological parameters and other welding conditions on welding quality is analyzed, and an outlook on future research and development is provided. This paper can serve as a useful reference for both fundamental research and engineering applications in this field.

Finite Element Study of the Cutting Mechanics of the Three Dimensional Rock Turning Process

2015 ◽  
Author(s):  
Demeng Che ◽  
Jacob Smith ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Polycrystalline Diamond ◽  
Close Correlation ◽  
Experimental Results ◽  
Failure Behavior ◽  
Fe Model ◽  
Gas Drilling ◽  
Cutting Mechanics

The unceasing improvements of polycrystalline diamond compact (PDC) cutters have pushed the limits of tool life and cutting efficiency in the oil and gas drilling industry. However, the still limited understanding of the cutting mechanics involved in rock cutting/drilling processes leads to unsatisfactory performance in the drilling of hard/abrasive rock formations. The Finite Element Method (FEM) holds the promise to advance the in-depth understanding of the interactions between rock and cutters. This paper presents a finite element (FE) model of three-dimensional face turning of rock representing one of the most frequent testing methods in the PDC cutter industry. The pressure-dependent Drucker-Prager plastic model with a plastic damage law was utilized to describe the elastic-plastic failure behavior of rock. A newly developed face turning testbed was introduced and utilized to provide experimental results for the calibration and validation of the formulated FE model. Force responses were compared between simulations and experiments. The relationship between process parameters and force responses and the mechanics of the process were discussed and a close correlation between numerical and experimental results was shown.

Piezoelectric Actuators With Active and Passive Frames

2013 ◽  
Author(s):  
Laura Tolliver ◽  
Xiaoning Jiang ◽  
Tian-Bing Xu
Keyword(s):  
Finite Element ◽  
Piezoelectric Materials ◽  
Active Vibration Control ◽  
Small Strain ◽  
High Energy ◽  
High Energy Density ◽  
Space Technology ◽  
Two Stage ◽  
Technology Applications ◽  
Passive Materials

Electromechanical actuators that generate large displacements, have large load capabilities, and demonstrate strong resonance characteristics are in great demand in the areas of precision positioning, active vibration control, and energy harvesting. Piezoelectric materials have been widely investigated for these applications because of their high energy density, quick response time, and relatively low driving voltages, but they demonstrate very small strain, typically about 0.1%. We present experimental and finite element results for two designs that use active and passive frames, respectively, to enhance the small strain in piezoelectric multilayer stacks. The first design, stacked-HYBATS, employs the synergetic contribution of d33 and d31 mode piezoelectric material. Finite element results show that this structure can generate over 50 microns of displacement and nearly 40 N of blocking force in a 36 mm × 22 mm × 10 mm footprint. The second design employs frames made from passive materials to form two stages of strain amplification in a 42 mm × 30 mm × 20 mm footprint. This two-stage design can produce over 600 microns of displacement and has a blocking force of 27 N. The active and passive materials of both designs can be varied to maximize displacement and/or blocking force. The stacked-HYBATS and the two-stage amplification system display favorable force-displacement capabilities and are promising for a variety of manufacturing and space technology applications.

NONLINEAR FINITE ELEMENT MODELING OF POST-TENSION RC AND RC BEAMS STRENGTHENED WITH NSM FRP RODS

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Belal Elharouney ◽  
Ayman Hussein ◽  
Ezz El-Deen Mostafa ◽  
Amr El-Nemr
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Load Capacity ◽  
Reinforced Concrete Beam ◽  
Experimental Results ◽  
Fe Model ◽  
Post Tension ◽  
Bending Loading ◽  
Frp Bars

The post-tensioned (PT) reinforced beams can provide a fast construction advantage through precast and cast-in-situ structural elements. However, due to the excessive increase in load capacity, especially when it comes to girder of bridges, the strengthening using Fiber-reinforced polymer (FRP) might be a solution. Near-surface mounted (NSM) is one of the methods used in strengthening cases, especially in the case of non-degraded concrete cover. Furthermore, very few researchers visited this area experimentally, which consider cost-effective. In this paper, two finite element models using the Abaqus program validated experimental results for both Post-tension beam and strengthening of the beam using NSM separately as preliminary models for combining both systems. PT reinforced concrete beam subjected to four-point bending loading as well as reinforced concrete beam strengthened with NSM using FRP bars subjected to two-point bending loading examined and validated through a 3D non-linear finite element (FE) model to be compared by the experimental results. This FE model considered the non-linear constitutive properties of concrete, yielding of steel, and the bond between strand, concrete, and FRP bars at NSM. The models were targeting the strengthening of existing Post tension girder beams of existing bridges structures. These modeling results showed a reasonable agreement with the tested beam results in terms of failure modes, the load capacity, load-deflection curve, and cracking behavior.

Elucidation of Welding Stability Based on Keyhole Configuration during High-Power Fiber Laser Welding

2011 ◽  
Vol 314-316 ◽  
pp. 941-944 ◽  
Author(s):  
Xiang Dong Gao ◽  
Qian Wen ◽  
Seiji Katayama
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
High Power ◽  
Continuous Wave ◽  
High Energy ◽  
High Energy Density ◽  
Deep Penetration ◽  
Characteristic Parameters ◽  
Fiber Laser Welding ◽  
Welding Stability

During deep penetration laser welding, a keyhole is formed in the molten pool due to the intense recoil pressure of evaporation. The formation of the keyhole leads to a deep penetration weld with a high aspect ratio and this is the most advantageous feature of welding by high-energy-density beams. The configuration and characteristics of a keyhole are related to the welding stability. In a fiber laser butt-joint welding of Type 304 austenitic stainless steel plate with a high power 10 kW continuous wave fiber laser, an infrared sensitive high-speed video camera was used to capture the dynamic images of the molten pools. The configurations of a keyhole were analyzed through image processing techniques such as median filtering, wiener filtering and gray level threshold segmentation to obtain the edge of a keyhole. The width and the area of a keyhole were defined as the keyhole characteristic parameters, and the deviation between the laser beam and weld center as a parameter reflecting the welding stability. By analyzing the change of the keyhole characteristic parameters during welding process, it was found that these parameters were related to the welding stability. Welding experimental results and analysis of the keyhole characteristic parameters confirmed that the welding stability could be monitored and distinguished by a keyhole configuration during high-power fiber laser welding.

scholarly journals Detection of Dynamic Modulus and Crack Properties of Asphalt Pavement Using a Non-Destructive Ultrasonic Wave Method

2019 ◽  
Vol 9 (15) ◽  
pp. 2946 ◽  
Author(s):  
Weiguang Zhang ◽  
Muhammad Arfan Akber ◽  
Shuguang Hou ◽  
Jiang Bian ◽  
Dong Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Wave Propagation ◽  
Ultrasonic Wave ◽  
Asphalt Concrete ◽  
Ultrasonic Testing ◽  
Experimental Results ◽  
Dynamic Moduli ◽  
Ultrasonic Wave Propagation ◽  
Non Destructive

Non-destructive ultrasonic testing has attained popularity due to its robustness and cost-effectiveness in monitoring the structural health and performance evaluation of pavements, thus replacing traditional methods. This paper presents the application of an explicit finite element method for the modeling of ultrasonic wave propagation through asphalt concrete. Prior to modeling, non-destructive ultrasonic testing was conducted on four different types of asphalt concrete (AC-13, SMA-13, AC-20, and AM-20). Based on acoustic information (wave velocity) obtained in non-destructive testing (NDT) and density, the dynamic moduli of these asphalt concretes were evaluated and used in numerical modeling of ultrasonic wave propagation using the commercial software package ABAQUS. The ultrasonic wave results obtained by numerical modeling were compared with experimental results. This comparison showed a good fit between the finite element (FE) results and the experimental results and confirmed a good FE approach for ultrasonic wave propagation. In addition, the influence of varying dynamic moduli, density, varying location, and crack size/depth on ultrasonic wave propagation was analyzed.

scholarly journals Research Status and Progress of Welding Technologies for Molybdenum and Molybdenum Alloys

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 279 ◽  
Author(s):  
Qi Zhu ◽  
Miaoxia Xie ◽  
Xiangtao Shang ◽  
Geng An ◽  
Jun Sun ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Laser Welding ◽  
Electron Beam Welding ◽  
High Energy ◽  
High Energy Density ◽  
Advantages And Disadvantages ◽  
Molybdenum Alloys ◽  
Current State ◽  
Electric Resistance Welding ◽  
Hyperbaric Environment

Owing to its potential application prospect in novel accident tolerant fuel, molybdenum alloys and their welding technologies have gained great importance in recent years. The challenges of welding molybdenum alloys come from two aspects: one is related to its powder metallurgy manufacturing process, and the other is its inherent characteristics of refractory metal. The welding of powder metallurgy materials has been associated with issues such as porosity, contamination, and inclusions, at levels which tend to degrade the service performances of a welded joint. Refractory metals usually present poor weldability due to embrittlement of the fusion zone as a result of impurities segregation and the grain coarsening in the heat-affected zone. A critical review of the current state of the art of welding Mo alloys components is presented. The advantages and disadvantages of the various methods, i.e., electron-beam welding (EBW), tungsten-arc inert gas (TIG) welding, laser welding (LW), electric resistance welding (ERW), and brazing and friction welding (FW) in joining Mo and Mo alloys, are discussed with a view to imagine future directions. This review suggests that more attention should be paid to high energy density laser welding and the mechanism and technology of welding Mo alloys under hyperbaric environment.

Interference Character Analysis of Multi-Ring Composite Flywheel Rotor

2013 ◽  
Vol 312 ◽  
pp. 421-424
Author(s):  
Guang Xi Li ◽  
Zhao Ding ◽  
Lin He ◽  
Li Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Gradient ◽  
High Energy ◽  
High Energy Density ◽  
Interference Condition ◽  
Composite Flywheel ◽  
Rotor Design ◽  
Radial Strength ◽  
Flywheel Rotor

In order to improve the radial strength of energy storage flywheel, this paper design and analyses the multi-ring flywheel rotor in different conditions by finite element method. From the results, we can confirm that interference condition is critical influence on the stress gradient of the rim. The results can provide a guide for high energy density multi-ring composite flywheel rotor design.

Investigation on Mechanical Properties of Pulsed Nd:YAG Laser Welding on AISI 304 Stainless Steel to AISI 1008 Steel

2011 ◽  
Vol 117-119 ◽  
pp. 402-408
Author(s):  
Shazarel Shamsudin ◽  
Phoon Chee Yoon
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Laser Welding ◽  
High Energy ◽  
High Energy Density ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Pulsed Nd:Yag Laser Welding

Product with low cost, lightweight and enhanced mechanical properties were the main reasons welding dissimilar materials thrived by most of the industries. The laser welding technique which has high-energy density beam was found suitable of carrying this task. This paper attempts to investigate welding of AISI 304 stainless steel to AISI 1008 steel through Nd:YAG pulse laser method. The main objective of this study was to find out the weldability of these materials and investigate the mechanical properties of the welded butt joints. Peak power, pulse duration and weld speed combinations were carefully selected with the aims of producing weld with a good tensile strength, minimum heat affected zone (HAZ) and acceptable welding profile. Response surface methodology (RSM) approach was adopted as statistical design technique for tensile strength optimization. Statistical based mathematical model was developed to describe effects of each process parameters on the weld tensile strength and for response prediction within the parameter ranges. The microstructure of the weld and heat affected zones were observed via optical microscope. The results indicate the developed model can predict the response within ±9% of error from the actual values.

scholarly journals An Experimental Simulation to Validate FEM to Predict Transverse Young’s Modulus of FRP Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
V. S. Sai ◽  
M. R. S. Satyanarayana ◽  
V. B. K. Murthy ◽  
G. S. Rao ◽  
A. S. Prasad
Keyword(s):  
Finite Element ◽  
Experimental Results ◽  
Experimental Simulation ◽  
Metallic Materials ◽  
Hexagonal Packing ◽  
Frp Composites ◽  
Young’S Moduli ◽  
Analytical Approaches ◽  
Transverse Modulus ◽  
Good Agreement

Finite element method finds application in the analysis of FRP composites due to its versatility in getting the solution for complex cases which are not possible by exact classical analytical approaches. The finite element result is questionable unless it is obtained from converged mesh and properly validated. In the present work specimens are prepared with metallic materials so that the arrangement of fibers is close to hexagonal packing in a matrix as similar arrangement in case of FRP is complex due to the size of fibers. Transverse Young’s moduli of these specimens are determined experimentally. Equivalent FE models are designed and corresponding transverse Young’s moduli are compared with the experimental results. It is observed that the FE values are in good agreement with the experimental results, thus validating FEM for predicting transverse modulus of FRP composites.

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